NASA Astrobiology Institute Director's Corner

One of the most satisfying aspects of astrobiology is the quality of the students and young researchers it attracts. I am particularly gratified by the quality of a recent applicant pool to the NAI Postdoctoral Fellowship Program (a part of the NASA Postdoctoral Program administered by the Oak Ridge Associated Universities) and the individuals we were able to select. I'd like to tell you a little about them.

Oleg Abramov is going to be working with Steve Mojzsis of the NAI's University of Colorado team studying the "Habitability of Early Earth: Thermal Modeling of the Lithosphere During the Late Heavy Bombardment." He will assess the habitability of early Earth during the late heavy bombardment using ancient detrital zircons and solar system dynamics techniques to constrain the characteristics of the bombardment, and thermal modeling to assess how much of the near-surface may have been habitable and for what periods of time.

Oleg received his doctorate at the University of Arizona under David Kring, a professor in the Lunar and Planetary Laboratory. Interestingly, Oleg's bachelor degree is in biology! Following that degree, he worked for a biotechnology company for two years. While a U of A graduate student, he continued his biological education with substantial coursework in microbiology. Oleg thus embodies the interdisciplinarity of astrobiology in a single individual. It is one of NAI's goals to help develop this kind of young researcher, and we are particularly pleased to have the opportunity to contribute to Oleg's career development and welcome him to the NAI.

Jennifer Biddle will be working with Andreas Teske of the University of North Carolina at Chapel Hill, a member of NAI's Marine Biological Laboratory (MBL) team. Jen will be studying microbes in marine sediments, particularly those responsible for anaerobic methane oxidation. It was long thought that microbial methane oxidation occurred only aerobically. Since methane production may have been one of life's earliest metabolisms on Earth, it's important to understand both the potential sources and sinks of methane on other worlds. The discovery of anaerobic microbial methane oxidation raises the possibility that this process could also play a role in the methane balance on other planets with a microbial ecosystem and a reducing environment.

An attractive aspect of Jen's work is that it will develop and strengthen connections between several current and former NAI teams. Jen did her doctoral work in the NAI Penn State team, collaborating with members of the MBL team, as part of a larger project led by the University of Rhode Island alumni team. Her postdoctoral work will involve all of these teams as well as the UCLA team and, of course, the University of North Carolina. This will be a great contribution to NAI's continuing goal of building collaborative connections across the astrobiology community.

Curtis Cooper will be working with Alex Pavlov of the University of Arizona team. Interestingly, Alex is himself an alumnus of this same NAI Fellowship Program, making Curtis our first "2nd generation" Postdoctoral Fellow! Curtis will conduct "Three-dimensional modeling of habitable zones and the paleoclimates of the terrestrial planets." Much of the past work to define habitable zones around the sun and other starsplanet-star distances at which water can exist in liquid form on the planet's surface--has relied on one-dimensional radiative-convective atmospheric models. But as we all know, planetary atmospheres transfer the received stellar (or solar) energy from regions that receive a relatively large amount (e.g., the tropics on Earth) to regions that receive much less (e.g., Earth's poles). Three-dimensional models are therefore essential to understand more accurately the conditions likely to be present on extrasolar terrestrial planets, thus potentially affecting our understanding of extrasolar habitable zones, and the conditions that were present early in the history of the terrestrial planets in this solar system. We look forward to Curtis' contributions to these major problems in astrobiology.

Finally, Matt Pasek will address fundamental questions about the origin and early development of life on Earth with Jonathan Lunine of the University of Arizona team. One central question that Matt will address is "what was the phosphorus source that enabled the formation of the first phosphorylated biomolecules?" Such biomolecules, which include DNA, RNA, ATP, and phospholipids, are essential to life. Yet most mineral phosphate on Earth is inactive, incapable of reacting with organic compounds to form biomolecules. Matt's hypothesis is that meteoritic phosphorus, delivered to Earth in the form of schreibersite [(Fe,Ni)3P], a common mineral in iron-rich meteorites, reacts naturally with water to produce the active phosphorus needed for biomolecule-forming reactions. If Matt demonstrates that organophosphates could have been produced on early Earth by this mechanism, it will provide a possible pathway for the development of one of life's most central characteristics, and potentially link the early heavy bombardment (recall Oleg Abramov's study described above) with the origin and early evolution of life.

Please join me in welcoming these outstanding young researchers to the NAI.

Carl Pilcher

Director, NAI

[Source: NAI newsletter]

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